The most impressive of the movies I've seen so far in "Sintel".
Also, I thought this might be of interest. This is a documentary of how "Sintel" was made. The irony here, though, is that "Sintel" is 15 minutes long and the documentary is 1 hour long (4x longer than the movie itself).
Here is the live action short I mentioned earlier. It's called "Tears of Steel". It really is cool. The effects are pro-level in my opinion.
On a more light hearted side, here is a "cartoon" called "Big Buck Bunny". It is very funny, but might not be OK for very young kids.
The last movie is "Alien Obsession". This movie is narrative (no actors) but is very cool in it's story telling. The level of detail in al the models is INCREDIBLE.
There are other movies, but I'll leave it to you to find them on youtube and have some fun in the world of discovery.
Next is a very cool tutorial I alluded to in my column. This video explains in careful detail how to quickly (and I mean QUICKLY) using a simple Google API and Blender. Something to be aware of. I downloaded the information for Wrigleyville in about 30 seconds, but my friend very residential, vanilla structures, took almost 5 minutes. Weird that the much more complex neighborhood would download much faster, but it did.
Here is a couple of links to sites that have downloadable material to read and follow step by step for beginners. Trust me, no skills are needed, just a desire to learn something cool and have fun trying things.
BlenderCourse Basics v2.2 An Introdution to Blender 3d
I hope you enjoy the movies and find the tutorials interesting enough to look for more (there are literally 1000's of video tutorials on youtube for Blender 3d., teaching any nuance you want or how to make a specifuc object).